Welcome to tagrissoandme.co.uk*
This website is intended only for UK patients who have been prescribed TAGRISSO® (osimertinib)
*This website has been produced and funded by AstraZeneca UK.
Like all medicines, osimertinib can cause some side effects, although not everyone will get them.1 On this page you can find out more about the possible side effects of treatment plans including osimertinib. For a full list of side effects, please refer to the Patient Information Leaflet which can also be found inside the package of your medicine.
Your cancer care team will have chosen a treatment plan that is specific to your individual needs and your treatment goals. This means you may be taking osimertinib alone, following, or alongside another treatment. For example, you may take it with chemotherapy or after chemoradiotherapy. The side effects you may get depend on which treatments are part of your cancer care plan. Find out more here.
Your healthcare team may adjust the dose, pause, or stop treatment with osimertinib depending on the side effects you experience. If you have questions or concerns about any side effects, talk to your healthcare team. They are there to support and give you advice.
Reporting side effects
If you get any side effects, talk to your doctor, nurse or pharmacist. This includes any possible side effects not listed in the Patient Information Leaflet. You can also report side effects directly via the Yellow Card Scheme, website: http://yellowcard.mhra.gov.uk/. By reporting side effects you can help provide more information on the safety of medicines.
Side effects can also be reported to AstraZeneca in the following ways:
Explore ways to manage side effects on the Tips on managing side effects page. You can also read more advice in the 'Supporting your treatment journey' information booklet on the Resources page.
Click on the tab below that relates to your treatment plan to find out more about your potential side effects. You can read more important safety information at the bottom of this page.
The frequency of side effects have been reported from clinical trials of osimertinib taken alone, with chemotherapy or following chemoradiotherapy.
- Osimertinib
- Osimertinib
with chemotherapy - Osimertinib following
chemoradiotherapy
Very common side effects (can affect more than 1 in 10 people taking osimertinib)1
Diarrhoea
Passing looser, watery or more frequent poo.2 This may come and go during treatment.
Skin and nail problems
This can look like itchy skin, rash or redness around the fingernails. These are more likely in areas of the body that are exposed to the sun.
Inflammation of the mouth
Also known as ‘stomatitis’, this can cause mouth ulcers or sores.
Loss of appetite
Not wanting to eat, finding it hard to eat big meals or not feeling hungry.
Changes in blood count
This can include a reduction in white blood cells and platelets. Your healthcare team will help you monitor this and let you know if further actions need to be taken.
Serious side effects1,3
These are side effects that need management from your healthcare team. Tell your doctor straight away if you notice any of the following serious side effects:
Sudden difficulty in breathing together with a cough or fever (common, can affect up to 1 in 10 people taking osimertinib)
This may be a sign of inflamed lungs, known as 'interstitial lung disease'.
Heart problems
- QTc prolongation (common, can affect up to 1 in 10 people taking osimertinib)
Changes in the electrical activity of the heart. This can include rapid or irregular heartbeats, dizziness, light-headedness, chest discomfort, shortness of breath and fainting.
- Cardiac failure (uncommon, can affect up to 1 in 100 people taking osimertinib)
When the heart does not pump enough blood. This can lead to shortness of breath, feeling overly tired and swollen ankles.
Eye problems (uncommon, can affect up to 1 in 100 people taking osimertinib)
These may look like watery eyes, sensitivity to light, eye pain, eye redness or vision changes.
Severe skin reactions
- Stevens-Johnson syndrome (SJS) (rare, can affect up to 1 in 1,000 people taking osimertinib)
- Toxic epidermal necrolysis (TEN) (it is not known how often this occurs in people taking osimertinib)
These are serious skin conditions that can start with fever or flu-like symptoms and lead to reddish circular patches with central blisters, peeling skin, ulcers in the mouth, throat, nose, genitals or eyes.
Bruising and fever (rare, can affect up to 1 in 1,000 people taking osimertinib)
A blood disorder known as ‘aplastic anaemia’ is a rare side effect that would need to be managed by your healthcare team. Bone marrow is a tissue in the body that is important for making blood cells. In aplastic anaemia, the bone marrow stops making enough new blood cells. Signs of aplastic anaemia include ongoing fever, bruising or bleeding more easily, feeling more tired than usual or infections that last a long time.
Hepatitis B reactivation (it is not known how often this occurs in people taking osimertinib)
Osimertinib can cause hepatitis B virus to become active again. Tell your doctor, pharmacist or nurse if you have ever had or might now have a hepatitis B infection, if you get tiredness that is getting worse, yellowing of your skin or yellowing of the white parts of your eyes.
Common side effects (can affect up to 1 in 10 people taking osimertinib)1,3
Nosebleed
This side effect is usually mild. It happens when there is bleeding from inside the nose.4
Hair thinning
This side effect is usually mild. It can involve hair falling out more than usual or hair becoming thinner.5
Hives
Also known as 'urticaria', this side effect can include itchy, raised patches anywhere on the skin. They may be pink or red and round in shape. Tell your doctor if you notice this side effect.
Skin greying or darkening
Also known as 'hyperpigmentation', this can involve patches of skin becoming darker or grey.
Hand-foot syndrome
This may include redness, swelling, tingling or a burning sensation, with cracking of the skin on the palms of the hands and/or soles of feet. These types of side effects can usually be treated with creams and lotions.
Muscle spasms
This can feel like tightening or cramping in the muscles.6
Increase of creatinine or creatine phosphokinase in the blood
- Creatinine is a substance made by the body and removed by the kidneys. This side effect is usually mild
- Creatine phosphokinase is an enzyme released into the blood when muscle is damaged
These side effects need to be managed by your healthcare team. Before and during your treatment, they will test your blood and let you know if any actions need to be taken.6
If you are having chemotherapy alongside osimertinib, you may have different side effects than if you were just taking osimertinib alone. This is because chemotherapy works in a different way to osimertinib.
Here, you can learn more about some of the side effects that you may experience:1
Very common side effects (can affect more than 1 in 10 people taking osimertinib with chemotherapy)1,3
Increase of a substance in the blood called creatinine
This is made by the body and removed by the kidneys. This side effect needs to be managed by your healthcare team. Before and during your treatment, they will test your blood and let you know if any action needs to be taken.7–9
Nausea and vomiting
Chemotherapy drugs may make you feel sick (nauseous) or be sick (vomit).2
Diarrhoea
Passing looser, watery or more frequent poo.2 This may come and go during treatment.
Skin and nail problems
This can look like itchy skin, rash or redness around the fingernails. These are more likely in areas of the body that are exposed to the sun.
Inflammation of the mouth
Also known as ‘stomatitis’, this can cause mouth ulcers or sores.
Loss of appetite
Not wanting to eat, finding it hard to eat big meals or not feeling hungry.
Changes in blood count
This can include a reduction in white blood cells and platelets. Your healthcare team will help you monitor this and let you know if further actions need to be taken.
Serious side effects1,3
These are side effects that need management from your healthcare team. Tell your doctor straight away if you notice any of the following serious side effects:
Sudden difficulty in breathing together with a cough or fever (common, can affect up to 1 in 10 people taking osimertinib with chemotherapy)
This may be a sign of inflamed lungs, known as 'interstitial lung disease'.
Heart problems
- QTc prolongation (common, can affect up to 1 in 10 people taking osimertinib with chemotherapy)
Changes in the electrical activity of the heart. This can include rapid or irregular heartbeats, dizziness, light-headedness, chest discomfort, shortness of breath and fainting.
- Cardiac failure (common, can affect up to 1 in 10 people taking osimertinib with chemotherapy)
When the heart does not pump enough blood. This can lead to shortness of breath, feeling overly tired and swollen ankles.
Eye problems (uncommon, can affect up to 1 in 100 people taking osimertinib with chemotherapy)
These may look like watery eyes, sensitivity to light, eye pain, eye redness or vision changes.
Common side effects (can affect up to 1 in 10 people taking osimertinib with chemotherapy)1,3
Nosebleed
This happens when there is bleeding from inside the nose.4
Hair thinning
This can include hair falling out more than usual or hair becoming thinner.5
Itchy skin
This is also known as ‘pruritus’. Using moisturisers regularly on the skin can help with this.
Target lesions
These are rashes that can look like rings on the skin. This is also known as ‘erythema multiforme’.
Hives
Also known as 'urticaria', this side effect can include itchy, raised patches anywhere on the skin. They may be pink or red and round in shape. Tell your doctor if you notice this side effect.
Skin greying or darkening
Also known as 'hyperpigmentation', this can involve patches of skin becoming darker or grey.
Hand-foot syndrome
This may include redness, swelling, tingling or a burning sensation, with cracking of the skin on the palms of the hands and/or soles of feet. These types of side effects can usually be treated with creams and lotions.
Muscle spasms
This can feel like tightening or cramping in the muscles.6
Increase of creatine phosphokinase in the blood
This is an enzyme released into the blood when muscle is damaged. This side effect needs to be managed by your healthcare team. Before and during your treatment, they will test your blood and let you know if any actions need to be taken.6
If you are having osimertinib following chemoradiotherapy, you may have different side effects than if you were just taking osimertinib alone. This is because chemoradiotherapy works in a different way to osimertinib.
Here, you can find out more about some of the side effects that you may experience:1
Very common side effects (can affect more than 1 in 10 people taking osimertinib after chemoradiotherapy)1,3
Lung inflammation
Chemoradiotherapy can sometimes cause inflammation in the lungs. This is called ‘radiation pneumonitis’.3 It can cause a cough or shortness of breath. This side effect needs to be managed by your healthcare team.10 Talk to your healthcare team straight away if you have a cough or shortness of breath that is getting worse.
Nausea and vomiting
Chemotherapy drugs may make you feel sick (nauseous) or be sick (vomit).2
Diarrhoea
Passing looser, watery or more frequent poo.2 This may come and go during treatment.
Skin and nail problems
This can look like itchy skin, rash or redness around the fingernails. These are more likely in areas of the body that are exposed to the sun.
Inflammation of the mouth
Also known as ‘stomatitis’, this can cause mouth ulcers or sores.
Loss of appetite
Not wanting to eat, finding it hard to eat big meals or not feeling hungry.
Changes in blood count
This can include a reduction in white blood cells and platelets. Your healthcare team will help you monitor this and let you know if further actions need to be taken.
Increase of a substance in the blood called creatinine
This is made by the body and removed by the kidneys. This side effect needs to be managed by your healthcare team. Before and during your treatment, they will test your blood and let you know if any action needs to be taken.6
Serious side effects1,3
These are side effects that need management from your healthcare team. Tell your doctor straight away if you notice any of the following serious side effects:
Sudden difficulty in breathing together with a cough or fever (common, can affect up to 1 in 10 people taking osimertinib after chemoradiotherapy)
This may be a sign of inflamed lungs, known as 'interstitial lung disease'.
QTc prolongation (uncommon, can affect up to 1 in 100 people taking osimertinib after chemoradiotherapy)
Changes in the electrical activity of the heart. This can include rapid or irregular heartbeats, dizziness, light-headedness, chest discomfort, shortness of breath and fainting.
Eye problems (uncommon, can affect up to 1 in 100 people taking osimertinib after chemoradiotherapy)
These can include watery eyes, sensitivity to light, eye pain, eye redness or vision changes.
Common side effects (can affect up to 1 in 10 people taking osimertinib after chemoradiotherapy)1,3
Hair thinning
This can include hair falling out more than usual or hair becoming thinner.5
Hives
Also known as ‘urticaria’, these can look like itchy, raised patches anywhere on the skin. They may be pink or red and round in shape. Tell your doctor if you notice this side effect.
Muscle spasms
This can feel like tightening or cramping in the muscles.6
Increase of creatine phosphokinase in the blood
This is an enzyme released into the blood when muscle is damaged. This side effect needs to be managed by your healthcare team. Before and during your treatment, they will test your blood and let you know if any action needs to be taken.6
For a full list of side effects, please refer to the Patient Information Leaflet which can also be found inside the package of your medicine. Talk to your healthcare team if you have any questions or concerns.
Important safety information1,3
There is some important information you should be aware of before and during your treatment with osimertinib. Your healthcare team should talk to you about any reasons not to take osimertinib before you start treatment. If you have any concerns, remember they are there to answer any questions you have.
You can click through the topics below to learn more.
Talk to your healthcare team before taking osimertinib if you have:
- Had inflammation of your lungs (a condition called ‘interstitial lung disease’)
- Had heart problems – your doctor may want to keep a close eye on you
- A history of eye problems
- Had or might now have a hepatitis B infection. This is because osimertinib can cause hepatitis B virus to become active again. Tell your doctor, pharmacist or nurse if you get tiredness that is getting worse, yellowing of your skin or yellowing of the white part of your eyes
Do not take osimertinib if:
- You are allergic (hypersensitive) to osimertinib or any of the other ingredients of this medicine (you can read more about these in section 6 of the Patient Information Leaflet)
- You are taking St. John’s Wort (Hypericum perforatum)
If you are not sure if any of the above apply to you, speak to your healthcare team. It is also important to look out for signs of ‘serious side effects’ when taking osimertinib. You can learn more about these in the ‘When to seek medical help’ section below.
While taking osimertinib, you must contact your healthcare team straight away if you have:
- Fever or flu-like symptoms followed by ulcers on your mouth, throat, nose, genitals or eyes
- Sudden breathlessness with cough or fever
- An unusual heartbeat, feeling dizzy, chest discomfort or fainting
- Ankle swelling
- Persistent fever, bruising or bleeding more easily or recurrent infections
- Increasing tiredness
- Changes to your eyes: watery eyes, sensitivity to light, eye pain, eye redness or vision changes
- Changes to your skin: reddish target-like marks on the skin, peeling skin or circular patches (which may have blisters) following fever or flu-like symptoms
It is really important to tell your healthcare team if you are currently taking, thinking about taking or have recently taken any other medicines. This includes prescription medicines, herbal medicines and medicines that you received without a prescription (for example, medicines from the pharmacy). Do not take osimertinib if you are taking St. John’s Wort (Hypericum perforatum).
Osimertinib has not been studied in children or adolescents. It is really important that you do not give this medicine to anyone under the age of 18 years.
Pregnancy
You must not take osimertinib if you are pregnant. This is because it may harm the baby. If you are planning to become pregnant or if you become pregnant while taking osimertinib, tell your healthcare team straight away. If your partner becomes pregnant while you are taking osimertinib, tell your healthcare team immediately.
Contraception
You must use contraception to protect against pregnancy during your treatment and after finishing treatment:
- Women should use contraception for 2 months after finishing treatment
- Men should use contraception for 4 months after finishing treatment
The type of contraception you need to use may be different to normal. Your healthcare team can advise you on what types of contraception to use. The Patient Information Leaflet in your medicine box also has more information.
Breastfeeding
If you have a baby, you must not breastfeed while taking osimertinib. It is not known if this causes a risk to your baby.
Where can I find more information about side effects?
References:
- Tagrisso 40 mg and 80 mg film coated tablets. Patient Information Leaflet.
- Macmillan Cancer Support. Side effects of chemotherapy. Available at: https://www.macmillan.org.uk/cancer-information-and-support/treatment/types-of-treatment/chemotherapy/side-effects-of-chemotherapy Accessed October 2026.
- Tagrisso 40 mg and 80 mg film coated tablets. Summary of product characteristics.
- Patient.info. Nosebleed. Available at: https://patient.info/ears-nose-throatmouth/nosebleed-epistaxis-leaflet Accessed October 2026.
- Macmillan Cancer Support. Hair loss. Available at: https://www.macmillan.org.uk/cancer-information-and-support/impacts-of-cancer/hair-loss Accessed October 2026.
- Macmillan Cancer Support. Osimertinib (Tagrisso). Available at: https://www.cancerresearchuk.org/about-cancer/treatment/drugs/osimertinib#what-are-the-side-effects-of-osimertinib Accessed October 2026.
- Carboplatin 10 mg/ml Intravenous Infusion. Summary of product characteristics.
- Cisplatin 1 mg/ml concentrate for solution for Infusion. Summary of product characteristics.
- Pemetrexed 25 mg/ml concentrate for solution for infusion. Summary of product characteristics.
- Cancer Research UK. Chest radiotherapy side effects. Available at: https://www.cancerresearchuk.org/about-cancer/treatment/radiotherapy/side-effects/chest Accessed October 2026.
GB-77676 | DOP: October 2026
Reporting side effects
If you get any side effects, talk to your doctor, nurse or pharmacist. This includes any possible side effects not listed in the Patient Information Leaflet. You can also report side effects directly via the Yellow Card Scheme, website: https://yellowcard.mhra.gov.uk. By reporting side effects you can help provide more information on the safety of medicines.
Side effects can also be reported to AstraZeneca in the following ways:
No imagery of real patients has been used on this site.
© AstraZeneca 2026. All rights reserved
GB-76796| DOP: October 2026
